Numerous processes have been developed for changing the fluorine content of halogenated hydrocarbons using chromium containing catalysts. These include increasing the amount of fluorine of halogenated hydrocarbons which are not fully fluorinated, decreasing the fluorine content of halogenated hydrocarbons containing fluorine, and redistributing the number of fluorine atoms among two or more hydrocarbon molecules which are not fully fluorinated.
Various catalysts have been proposed for use in facilitating processes such as hydrofluorination, hydrochlorination (i.e., fluorine substitution by chlorine) and disproportionation which involve halogenated hydrocarbons. See, e.g., L. E. Manzer et al., Adv. Catal. 39, pp. 329-350 (1993). A well known class of art catalysts includes chromium supported on alumina, fluorinated alumina or aluminum fluoride. Typically these materials are prepared by depositing a soluble salt of chromium on an alumina or aluminum fluoride support. While this method does produce a combination catalyst, the support material and the material deposited thereon are not uniformly mixed. Techniques such as coprecipitation which rely upon physical characteristics of individual components (e.g., solubility) also typically yield non-homogeneously dispersed products due to differences in physical and chemical properties of the components. There is an interest in developing means for a more homogeneous dispersion of chromium on an aluminum fluoride support which can be used as a catalyst for changing the fluorine content of halogenated hydrocarbons.